通过共享DCC(灵活DDR)实现：

int bri 2/0

undo dialer enable-circular                   

dialer-group 1                                

dialer bundle-member 1                       

dialer bundle-member 2  

interface Dialer0

link-protocol ppp

ppp pap local-user usera password simple passwd

ip address ppp-negotiate

dialer user usera

dialer bundle 1                                     

dialer number 1234                                 

#

interface Dialer1

link-protocol ppp

ppp chap user usera

ppp chap password simple passwd

ip address ppp-negotiate

dialer-group 1

dialer user usera

dialer bundle 2                                

dialer number 4567